1. Field of the Invention
This invention relates to a method of producing an article of thermosetting resin and to a novel thermosetting article.
It is generally known in the laminating art that a laminated article can be prepared by several methods. (1). In one method, a core of the desired shape and density is pre-cut to the proper size and a reinforcing layer, often a resin-reinforced glass layer, is then glued on the core using the proper adhesive. If necessary, the assembly is then placed in a mold and cured. (2). Another method, often referred to as the "hand easy-up" method, involves producing an article in or on a mold. This method includes coating the molding surface with a release agent, laying a fibrous reinforcing material, for example, a layer of glass fiber, on the molding surface, impregnating the fibrous layer with an uncured, liquid thermosetting resin, and allowing the resin to cure and harden. The liquid resin is conventionally applied by hand. (3). In still another method, particularly useful in the ski industry (see Article concerning "K-2" skis in the Seattle Times, Jan. 31, 1971), the core is pre-cut and a resin impregnated glass fiber mass is then wrapped around the core, the assembly is placed in the mold and heated and pressured so that the resin properly cures. In this case, the resin acts not only as an adhesive agent, but also the resin laminate combination envelopes the entire core.
Disadvantages of the first and third methods is that the core must be pre-cut exactly to fit the mold which is a time-consuming step, especially when working with difficult shapes such as skis. In the hand easy-up method, the manual application of the resin is time-consuming and costly; moreover, the quality of the impregnated product is not the same over different areas thereof as a result of non-uniform impregnation with the resin.
It is generally known in the art that a foam sheet can be mildly impregnated with a thermosetting resin, partially compressed, and the resin allowed to cure in order to form a relatively strong, rigid article. Further, other materials, such as metals, wood, synthetic plastic material, or textile materials, can be used to face the resin impregnated foam article either before or after molding the foam (see Great Britain Pat. No. 911,427, issued Nov. 28, 1962). It is also known that a thermosetting resin reinforced with a glass fiber mat (described above) can be laminated to a thermosetting resin impregnated polyurethane foam, the foam being employed to improve the surface appearance of the final article (see Great Britain Pat. No. 1,068,503, issued May 10, 1967). In these methods, it is necessary to form the facing material separate from the impregnated foam and laminate the two thereafter.
It has also been suggested in British Pat. No. 1,209,974 to Konig, published Oct. 28, 1970, that an article is formed by mixing compressible filler particles of foamed material with fibrous reinforcing material and a synthetic resin, then laying a fibrous reinforcing material on the mixture, and compressing the assembly to distribute the resin throughout the core and fibrous layer. However, this method requires that fibers be distributed in the core to get the desired results.